Pesticide spraying apparatus

ABSTRACT

An improved pesticide spray apparatus is disclosed which incorporates an independently controlled chemical delivery system with an independently controlled air delivery system for increased pesticide application efficacy. The air delivery system includes a blower unit which is aerodynamically efficient and a unique protective shroud system which prevents the undesirable corrosion of the electrical and hydraulic components of the spray system.

BACKGROUND OF THE INVENTION

The present invention relates to an improved pesticide sprayingapparatus for use in the application of agricultural pesticides. Thisimproved apparatus utilizes a rotary atomizer, such as the atomizerdescribed in U.S. Pat. No. 4,225,084, as a pesticide droplet dischargeunit.

The most common method of applying agricultural pesticides necessitatesthe use of large volumes of water as a carrier for the chemical.However, many problems have been encountered which have caused theagricultural industry to look for alternative methods of application.One of the major problems in the use of water as a carrier is that 20-30gallons of water per application acre is required to achieve acceptablecoverage. The need for such large volumes creates hardships due to thecontainment and transfer operations needed to replenish the sprayerholding tanks with the appropriate chemical mix. In some instances, theoperator must discontinue spraying operations every few acres toreplenish his tanks. Further, most commonly used pesticides available ontoday's market are not water soluble, but rather are oil-based. Theseoil-based pesticides require additives which allow the pesticide toproperly mix with the water. Without the additives, the water and oilpesticide mixture sometimes forms an inversion during agitation; anundesirable condition. Problems have also been encountered inenvironments that are hot, dry and windy as the water carrier mayevaporate entirely within seconds after application, thereby notallowing the pesticide chemical to be effectively absorbed.

The rotary atomizer technology, such as that disclosed in U.S. Pat. No.4,225,084, has made available a pesticide applicator which is capable ofmore closely regulating the volume of chemical used and therebyregulating the chemical cost to the farmers. The rotary atomizer unitprovides for an ultra low volume, controlled droplet discharge whichgreatly enhances reduced chemical application rates and provides forimproved pest control. Such atomizers have been found to be acceptableapplicators for a non-water approach to pesticide application. The useof the rotary atomizer promotes uniform droplet size and improvesdroplet density to increase the effectiveness of the chemical pesticidetreatment as compared to other conventional application methods.Further, the low volume design of the atomizer cup produces acceptableresults from both direct rate application and oil-based rateapplication, as an alternative to water based application.

As long as a sufficient number of droplets of acceptable size can begenerated by the rotary atomizer, there is no need for a carrier. If alarger volume of droplets is necessary, a compatible oil carrier can beused. The use of vegetable oil as a replacement for water as a carrierhas solved several problems. Vegetable oil eliminates alkalinehydrolysis wherein the salts in the water neutralize the acid in thepesticide. Vegetable oil improves the efficacy of the pesticide chemicalsince it is biologically active and can be absorbed or digested by theplant or insect being treated. Vegetable oil greatly reduces the ratesof chemical volatility and the photodecomposition of some pesticidechemicals. Also, vegetable oil resists washoff and spreads out toprovide a more even application.

Certain current models of the rotary atomizer type applicator use smallDC motors to drive the atomizers. Early versions of the DC motor drivesystems encountered problems in reliability because pesticide chemicalsbeing applied were highly corrosive to the atomizer unit and its drivesystems. As the drive system corrodes, power to the motors wasfrequently interrupted causing an inordinate amount of service and downtime. Further, the commonly used DC electric motors are operable only ata limited range of speeds; for example four distinctly different speeds.The limited speed settings can cause incorrect application rates. Forinstance, if the atomizer is set at too high a speed for wind conditionsat the time of application, the droplets will be quite fine and willdrift from the target area. However, if the speed of the atomizer isreduced to eliminate the drift of the pesticide, the large droplet sizewhich can result from the limitations on speed variations will result inwasted chemicals and will not provide adequate coverage.

In an attempt to correct these shortcomings, some rotary atomizers havebeen designed which use individual hydraulic drive motors. The use ofhydraulic motors has provided for a greater variation in speed settingsas the hydraulic motors are controlled by manually adjusting theirhydraulic flow. This approach has encountered significant problems inthat the hydraulic motors consume large volumes of high pressure oil;more oil than most small and medium size prime movers can providewithout the addition of an auxiliary hydraulic system. Further, sincethe motors are directly coupled to the atomizer cup, they must rotate at(whatever cup) speed is needed by the cup to adequately disperse thepesticide chemical. These cup speeds can approach 6,000 revolutions perminute in some applications. Such high speeds can create foaming in thehydraulic oil as well as overheat the oil. The hydraulic oil oftenreaches temperatures near or above design limits. In order to reduce theoverheating problems, auxiliary cooling systems have been required onall but the largest tractors which usually have such systems as standardequipment. These cooling systems prevent the breakdown of the hydraulicoil and, thereby, increase the life of all components which arelubricated by the hydraulic system. Even with large tractors and idealhydraulic systems, however, the individual hydraulic motors are known towear at uneven rates after only a few weeks of use. Long before theservice life of the motor is over, measurable differences betweenatomizer speeds will result in uneven application rates.

Other attempts to improve the efficacy of the rotary atomizer includethe use of small fans attached to the shaft at the bottom of theatomizer. These fans are intended to help direct the pesticide spray.The fans can be manually adjusted to provide a variable pitch toincrease and decrease air delivery speeds. They rotate at the same speedas the rotary atomizer and there are many limitations in their abilityto deliver desirable volumes of air. The fans are able to increase ordecrease air velocity at a given RPM only by adjusting the pitch of theblades. However, this adjustment must be manually made to eachindividual blade; a frustrating and time-consuming chore.

Application environments that need varying degrees of large droplets andlarge volumes of air or small droplets and small volumes of air cannotbe adequately treated without many time-consuming manual adjustmentsbeing made to the spray system by the operator. The operator has toleave the tractor platform and adjust each unit whenever change isrequired. Thus, when working in small fields where crop conditions oftenchange, the continual readjustment process can easily consume largequentities of an operator's time.

Therefore, it is the purpose of the present invention to provide animproved pesticide spraying apparatus capable of an infinite variety ofadjustable speeds at the rotary atomizer and further being capable of aninfinite variety of independently adjustable speeds of a fan blower toassist in dispersion of the pesticide chemical.

SUMMARY OF THE INVENTION

The improved pesticide spray apparatus of the present invention isdesigned to be mounted on a conventional spray boom. The spray unitconsists of three integrated component systems which independentlyprovide air delivery, droplet generation, and pesticide flow controls.The air delivery system of the present invention employs a blower whichincludes a fan and a tubular housing. The tubular housing directs theair driven downward by the fan to assist in the dispersion of thepesticide chemical leaving the rotary atomizer. The shape of the tubularhousing varies from a circular opening at the top of the tubular housingto an oval opening at the bottom of the tubular housing. The oval shapeflattens and widens the discharge pattern to provide overlap between theindividual sprayer units.

The fan member is mounted on a gearbox which is fixed to the top of aconventional spray boom. The gearbox is driven by a hydraulic motorwhich also is mounted on the spray boom. The present invention providesfor a plurality of spraying units to be positioned on a spray boom andthe single hydraulic motor is designed to drive all of the gearboxes ofall the spraying units. The gearbox is designed to provide a gear ratiowhich causes the fan member to rotate at twice the speed of thedriveshafts which connect the gearboxes to the motor, thus allowing thedriveshafts to be driven by a conventional gear type hydraulic motorwithout fear of foaming the hydraulic fluid or overheating the fluid.Conventional gear hydraulic motors have proven to be very efficient,generating little heat during their operation and requiring littleservicing during a long life.

The hydraulic motors are controlled by a flow control valve remotelyactuated by a linear actuator. The actuator control is mounted on theoperator platform or in the cab of the tractor, truck, or prime movercarrying the spray boom. Air volume delivery from the fans can thus beregulated independently of the atomizer speed with an infinite varietyof speeds without necessitating shutdown of the spraying system orrequiring the operator to dismount from his station.

The present invention further provides for a unique aerodynamic tubularhousing which prevents unnecessary turbulence in the air column beingdelivered past the rotary atomizer. A boom shroud designed to cover theboom member, the driveshafts and the pesticide anti-siphon valvestraverses the interior of the tubular housing. A center shroud designedto cover the gearbox and the electric motor is integrally engaged withthe boom shroud along the centerline of the housing. The shrouds aredesigned to have generally elliptical shape to provide the smoothestpossible flow of air over their surfaces. The tubular housing isdesigned to provide for a constant flow rate for the air column passingthrough the housing and over the shrouds. Thus, the shape of the tubularhousing continuously varies depending on the interior volume enclosed bythe shrouds. This adjustment eliminates constrictions and expansions inthe air column as it flows through the housing. This eliminatesundesirable pressure changes in the air column, thus minimizingundesirable turbulence.

The second major component of the present invention utilizes a rotaryatomizer, such as the Micron DR-4 assembly. The rotary atomizer isdriven by a DC electric motor with field control. It is capable of aninfinite variety of speeds from 0-6500 RPM. The motor of the rotaryatomizer is mounted on the underside of the spray boom and the atomizeris mounted on the shaft of the motor. The motor control is mounted onthe operator's platform. Since the atomizer speed is the same as themotor speed, droplet density can be changed quickly without shutdown ofthe spraying system.

It can be seen that the independently controlled variable speed blowerand the independently controlled variable speed rotary atomizer canprovide for any combination of high or low volume air coupled with highor low droplet density. This capability allows the operator to trulymanage the pesticide application process and tailor that process tofield conditions on a real time basis.

The last component of the present invention provides for control of theflow of the pesticide chemical to the atomizer cup. Uniform dropletgeneration of the desired size is possible only if the rate of chemicalflow remains constant. The reduced flow requirements of a pesticidechemical being applied without the usual water carrier means that only afew ounces of pesticide chemical are needed every minute at the atomizercup. This reduced flow requirement makes the handling of wettablepowders more difficult, since powders require constant agitation toavoid settling. For this reason, the feed system of the presentinvention is designed to recirculate in a closed loop. The pesticidesupply line passes an anti-siphon assembly which rations the pesticideto each atomizer cup and then returns excess pesticide chemical to thesuction side of the chemical feed pump. The chemical flow from the feedpump is regulated by an operator controlled solenoid valve.

Thus, it can be seen that the present invention provides the benefit ofindependent and variable air delivery to assist in dispersing thechemical droplets to match target conditions and offset the effects ofuncontrollable elements, thereby providing superior coverage.

The present invention further provides the major benefit ofindependently controlled variable droplet generation wherein the dropletdensity is adjusted to match the pesticide application rate withchanging environmental conditions.

The present invention provides for increased ease of adjustment to theair delivery system and droplet generation system in that thoseadjustments can be made while the systems are in operation with aminimum of delay.

The present invention also provides for improved electrical andhydraulic systems which reduce hydraulic and electric demands on theprime mover to offer greater versatility and reduced supportrequirements and costs.

Finally, the improved apparatus provides for shielded components throughthe use of the center shroud, boom shroud, and tubular housing therebyeffecting less maintenance and cleaning costs and providing betterprotection for the operator.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing two units of the improved pesticidespray apparatus mounted on a conventional spray boom.

FIG. 2 is a perspective view showing the two halves of the centershroud, boom shroud and tubular housing of the pesticide spray apparatusof the present invention.

FIG. 3 is a side view of the pesticide spray apparatus of the presentinvention with a center cutout showing the boom, gearbox, andanti-siphon apparatus.

FIG. 4 is a top view of the pesticide spray apparatus of the presentinvention.

FIG. 5 is a cutaway view along line 5--5 of FIG. 4.

FIG. 6 is a cutaway view along line 6--6 of FIG. 4.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention relates an improved pesticide spray apparatusdesigned to increase the efficacy of pesticide spray dispersion fromrotary atomizer units by directly and independently controlling threeintegrated component systems; the air delivery, the droplet generation,and the pesticide flow control.

Referring to FIGS. 1, 2 and 3, the air delivery system is shown tocomprise a blower which has a tubular housing 10 which is mounted on aconventional spray boom 1. In the preferred embodiment the tubularhousing is approximately 12 inches long. The shape of the tubularhousing 10 changes from a circular opening 12, located above the sprayboom 1, to an oval opening 14, located below the spray boom 1. The ovalopening 14 at the lower portion of the tubular housing 10 is preferredas the oval shape tends to flatten and widen the discharge pattern ofthe airflow exiting from the opening 14 to provide for completedischarge overlap between spray units. In the preferred embodiment, theimproved spray units are spaced on 40 inch centers across the spray boom1 and the oval opening 14 is designed to overlap the fan shapeddischarge of the spray units to provide a complete and efficientpesticide application.

Referring now to FIGS. 5 and 6, a fan member 16 is housed within thetubular housing 10 at a location proximate the circular opening 12. Thefan member is driven through a right angle gearbox 18, which in turn ismounted securely to the top side of the spray boom 1. In the preferredembodiment, the gearbox 18 is of aluminum construction and has a onehorsepower minimum capacity.

The gearbox 18 receives its rotational force input through thedriveshafts 20 which are connected to the gearbox by flexible couplers22, such as lovejoy couplers. The couplers 22 compensate for anymisalignment between the gearbox 18 and the driveshafts 20 and providefor the quick removal of the driveshafts 20 or gearbox 18 for servicing.The driveshafts 20 connect the spray units of a spray boom 1 section inseries and are driven by a single conventional gear hydraulic motor 62.Thus, on a conventional sprayer there are three boom sections with eachboom section including a series of improved pesticide spray units of thepresent invention spaced on 40 inch centers. The sprayers on each boomsection are interconnected together by driveshafts 20 which, in turn,are connected to a single hydraulic motor 62 located on the boomsection. Therefore, the sprayer will use three hydraulic motors; one forthe left boom section, one for the center boom section, and one for theright boom section.

Referring now to FIGS. 4 and 6, the fan members 16 of the spray unitsare either three-bladed or five-bladed fans depending on the designapplications and the volume of air needed for specific environmentalconditions. The fan members 16 are mounted on the output shaft 24 of theright angle gearbox 18 and are reverse threaded against the direction oftorque, thereby forcing the fan members 16 to self-tighten when thespray unit is in operation. A protective wire screen 26 is clippedacross the circular opening 12 to prevent contact with the fan member 16and to prevent the intrusion of unwanted objects into the tubularhousing 10. An aerodynamic cap 27 is screwed on the shaft end above thefan member 16.

In the preferred embodiment, each fan member 16 requires from 1/10 to1/5 horsepower at maximum RPM. The more blades on the fan member 16, thegreater the torque demand. Therefore, depending on the number ofpesticide spray units per boom member 1, the size of the hydraulic drivemotor 62 can be scaled accordingly. The hydraulic drive motors 62 foreach boom section, if the sprayer includes more than one boom section,are connected in series and, thus, all run at the same speed. Speed iscontrolled by a hydraulic flow control (not shown) which is connected toa 12-volt DC linear actuator (not shown). The linear actuator (notshown) receives its power from the tractor, truck or whatever primemover is carrying the spray boom 1. The operator control (not shown) forthe linear actuator (not shown) is mounted on the operator's platform orin the cab of the prime mover. Thus, the air volume moving through theblower unit can be controlled by increasing or decreasing the fan speedvia the actuator's electrical control. It has been shown that theresponse time is dependent upon the actuator speed, and usually rangesfrom 10-15 seconds for a full cycle. In this manner, the operator canquickly and easily change the delivery velocity of the air as the fieldconditions require. There is no need for the operator to stop thespraying apparatus or dismount from the operator platform.

The pesticide droplet generation system operates independently of theair delivery system. This is desirable since the operators will oftenencounter field situations where droplet density must be variedirrespective of the air delivery speed. In the preferred embodiment, thepesticide applicator is a rotary atomizer 28 such as a Micron DR-4. Therotary atomizer 28 is mounted to the underside of the spray boom 1 andis located directly below the oval opening 14 of the tubular housing 10.A variable speed electric motor 30 is directly coupled to the shaft 56of the rotary atomizer 28 to provide rotational power to the atomizer28. In the preferred embodiment, the electric motor 30 is a 12-volt DCvariable speed motor capable of an infinite number of speed settingsfrom 0-6500 RPM. The electrical wiring 32 for the electric motor 30 ismounted inside the spray boom 1. The electrical wiring 32 runs throughthe interior of the spray boom 1 and connects with the prime mover andreceives its power from the electrical system of the prime mover.Locating the electrical wiring harness inside the spray boom 1 protectsthe electrical wiring from the corrosive effects of the chemicalpesticides being applied through the system. The electric motors 30 ofeach spray unit are connected in series, thus allowing for therotational speed of all motors 30 of all spray units mounted on a boomsection 1 to be varied and controlled by one motor speed control unit(not shown). The motor speed control unit (not shown) is mounted next tothe control (not shown) for the linear actuator (not shown) on theoperator's platform or in the cab of the prime mover. Since the rotaryatomizer 28 is connected by a fixed shaft 56 to the variable speedelectric motor 30, the atomizer rotational speed will be the same as themotor speed and the droplet density of the pesticide chemical can bealtered quickly without need for discontinuing the spray application ordismounting from the cab. A unique aspect of the present inventionprovides for the independent controls for the rotational speed of therotary atomizer 28 and the rotational speed of the fan member 16 to beindependently varied, thereby providing any combination of high or lowair volume coupled with high or low droplet density. This capabilityprovides the operator with true control to manage all field conditionsduring the pesticide application process.

The present invention also provides a unique aerodynamic design for thetubular housing 10 and further provides for protective aerodynamicshrouds which cover and protect the interior components of the spraysystems which are located inside the tubular housing 10. Referring nowto FIGS. 2, 3 and 5, the aerodynamic shrouds will be described indetail. The center shroud member 34 is generally designed to enclose andcover the gearbox 18 and electric motor 30. In the preferred embodiment,the center shroud 34 is 1/2 of an ellipse with an eccentricity of 0.966.A bottom plate 36 is fixed to the center shroud 34 at a point locatedproximate the rotary atomizer 28. The center shroud 34 is aligned withthe central axis of the spray unit, that axis being defined by the axisextending through the center of the output shaft 24 of the gearbox 18and the shaft 56 of the rotary atomizer 28.

A boom shroud 38 is integrally connected to the center shroud 34 andextends across the width of the tubular housing 10 to cover and protectthe spray boom 1, driveshafts 20 and other interior components. The boomshroud, in the preferred embodiment, is a complete ellipse with aneccentricity of 0.942. The boom shroud 38 is aligned with the centerlineof the spray boom 1.

In the preferred embodiment, the center shroud 34 and the boom shroud 38are integrally molded together and are formed in two sections; a rightshroud section 40 and a left shroud section 42. The sections 40, 42 areadapted to fit around the spray boom 1 at their centerline.

Since the center shroud 34 and boom shroud 38 occupy volume within thetubular housing 10, the shape of the tubular housing 10 mustaerodynamically conform to compensate for the variations in thecross-sectional surface area of the flow tunnel of the tubular housingin order to prevent any unnecessary turbulence in the airflow as itmoves through the tubular housing. The present invention provides forsubstantially constant cross-sectional interior surface area on anylateral plane of reference within the tubular housing 10 from thecircular opening 12 to the oval opening 14. If the same interior surfacearea is not maintained as the air column is driven through the tubularhousing 10, zones of constriction and expansion will develop, causinghigh or low pressure turbulence. This turbulence is undesirable as itcould destroy the droplet pattern produced by the rotary atomizer 28.Therefore, the shape of the tubular housing is designed to variablycompensate for the shapes of the center shroud 34 and boom shroud 38 inthe interior of the flow tunnel.

The tubular housing 10 is also divided into sections; a right housingmember 44 and a left housing member 46. In the preferred embodiment, theright and left housing members 44, 46 engage the right and left shroudsections 40, 42 and operate to secure the shroud sections 40, 42 to thespray boom 1. The right housing member 44 and left housing member 46 areconnected together with over-center latches 48 which are locatedproximate the top of the tubular housing 10 and with hook hinges 49located proximate the bottom of the tubular housing 10. As the housingmembers 44, 46 are latched together, they engage and secure the shroudmembers 34, 38 to the spray boom 1. Thus, the entire aerodynamic blowerunit is firmly secured to the spray boom 1 and will incur no vertical,horizontal, and lateral movement. The latches 48 and hook hinges 49provide for easy removal of all shrouds from the boom 1. To remove theshroud members 34, 38 from the boom 1, the operator first removes theright housing member 44 and left housing member 46 from the spray boom1, leaving the boom shroud 38 and center shroud 34 on the spray boom 1.The right shroud section 40 and left shroud section 42 are thenremovable from the spray boom 1, providing quick and easy access to allinterior components. The shrouds 34, 38 act to protect all interiormechanical and electrical components of the spray system fromunnecessary exposure to the elements and pesticides. Even if someinfiltration occurs, the simple removal of all shrouds encouragesroutine cleaning.

Referring now to FIGS. 3 and 6, the pesticide flow control system willbe described. Uniform pesticide droplet generation of the desired sizeis possible only if the rate of chemical flow to the rotary atomizer cup28 remains constant. Since the present invention is designed for use inapplying pesticides without need for a water carrier, there are distinctreduced pesticide flow requirements for achieving a proper applicationrate. In many situations only a few ounces of pesticide chemical perminute must flow to the rotary atomizer 28 to achieve acceptablechemical dispersion. This reduced flow requirement makes difficult thehandling of such pesticides as wettable powders since those pesticidesrequire constant agitation to avoid settling. For this reason, thechemical feed systems of the present invention are a closed loop orrecirculating design. The supply lines 50 which are located on theinterior of the spray boom 1 are designed to pass each rotary atomizer28 and return lines 60 supply remaining chemical to the suction side ofthe chemical feed pump (not shown).

The supply lines 50 are engaged by atomizer supply lines 52 which extendthrough the spray boom 1 into anti-siphon assemblies 54. In thepreferred embodiment, the anti-siphon assemblies 54 are Spraying Systemsdesignation 18670. The anti-siphon assemblies 54 each include a filterand a rate control plate. The anti-siphon assemblies 54 are simplespring-loaded diaphragms that are set to open above 7 psi. When thepressure in the supply lines 50 of the pesticide feed systems exceedsthe threshold 7 psi, chemical flows through the filter and the ratecontrol plate orifice to the rotary atomizer 28. The feed tubes 58 tothe rotary atomizer 28 are connected to the anti-siphon assembly 54 bymeans of a quick attach connector 64.

An operator controlled solenoid valve (not shown) located in the supplyline 50 system controls the pesticide flow from the chemical feed pump(not shown). In the preferred embodiment, a check valve (not shown) isplaced in the chemical return line 60 to prevent loss of system pressureafter the solenoid closes. Further, the diaphragms located within theanti-siphon assembly 54 will seal as soon as the pressure in the supplysystem falls below 7 psi. Thus, the recirculating pesticide system willremain pressurized at this level until again placed in service,preventing air from entering the system and bringing a quicker responsewhen energized.

In the preferred embodiment, there are two separate independentpesticide supply systems. Each is fed from its own pump and reservoir.The two systems allow pesticides that address different problems to beused together, such as broadleaf herbicides and grass herbicides. Italso provides for the simultaneous application of chemicals that aretotally incompatible in tank mixtures, as well as chemicals that requirediffering application rates.

Electrical control of each solenoid is obtained by means of a on/offswitch positioned on the operator's platform proximate the controlswitches for the air delivery system and the pesticide atomizer speed.Thus, it can be seen that general area spraying as well as spot sprayingis possible. The quick response of the pressurized manifold allowsprecise application, regardless of ground speed. Total control of thechemical application process is available to the operator, enabling theoperator to adjust the application to meet varying environmentalconditions without incurring time-loss and frustrating manualadjustments to the spraying unit.

The foregoing description of the present invention is intended to beillustrative in nature and is not intended to be limiting upon the scopeand content of the following claims.

What I claim is:
 1. An improved pesticide spray apparatus comprising, incombination: at least one rotary atomizing member fixed to a boommember, means for supplying such pesticide to said rotary atomizingmember for dispersion, means for rotating said atomizing member, blowermeans for supplying a column of fluidized air, said blower meansincluding a fan member spaced from and opposed to said rotary atomizingmember, said blower means further including a housing member positionedon said boom member, said fan member being located within said housingmember, said housing member being of hollow cross section and havingopen ends, said first open end of said housing member beingsubstantially circular in cross section and said opposed open end ofsaid housing member being generally oval in cross section with the longaxis of said oval being parallel to the longitudinal axis of said boommember, said blower means further including a boom shroud member locatedwithin said housing member, said blower means further including a centershroud member located within said housing member between said fan memberand said rotary atomizing member, whereby during operation of said sprayapparatus said column of fluidized air is propelled by said fan memberthrough said housing member and around said boom shroud and said centershroud to envelope said rotary atomizing member and assist in dispersingsuch pesticides exiting said rotary atomizing member.
 2. The sprayapparatus of claim 1, wherein said rotary atomizing member and said fanmember are spaced apart and said fan member is positioned within one endof said housing member, said housing member extending from said fanmember to a point proximate said rotary atomizing member whereby saidrotary atomizing member is positioned adjacent said housing member. 3.The spray apparatus of claim 1, wherein said rotary atomizing memberincludes a cup member spaced from said boom member, a shaft memberconnected to said cup member and a motor means engaged with said shaftmember to rotate said cup member.
 4. The spray apparatus of claim 3wherein said motor means is fixed to said boom member.
 5. The sprayapparatus of claim 3 further including at least one pesticide flowcontrol means mounted on said boom member, said pesticide flow controlmeans being in communication with said supply means for regulating theflow rate of such pesticide to said cup member.
 6. The spray apparatusof claim 5, wherein said blower means includes means for driving saidfan member.
 7. The spray apparatus of claim 6, wherein means for drivingsaid fan member includes a second motor means mounted on said boommember and a gearbox in communication with both said motor means andsaid fan member.
 8. The spray apparatus of claim 7 further including adriveshaft interconnected between said second motor means and saidgearbox.
 9. The spray apparatus of claim 8, wherein said housing memberencloses said fan member, said gearbox, a portion of said driveshaft,said first motor means and said pesticide flow control means.
 10. Thespray apparatus of claim 9, wherein said fan member is located proximateone open end of said housing member.
 11. The spray apparatus of claim10, wherein said cup member is located adjacent the opposed open end ofsaid housing member outside of the cross-sectional plane of said opposedopen end of said housing member.
 12. The spray apparatus of claim 11,wherein said boom shroud member encases said portion of said boom memberand said portion of said driveshaft located within said housing member.13. The spray apparatus of claim 12, wherein said boom shroud member isgenerally elliptical in cross-section with the long axis of said ellipsebeing perpendicular to the longitudinal axis of said boom member andextending in a direction parallel to the longitudinal centerline of saidhousing member.
 14. The spray apparatus of claim 13, wherein said centershroud member encases said gearbox and said first motor means.
 15. Thespray apparatus of claim 14, wherein said center shroud member isgenerally elliptical in cross-section with the long axis of said ellipselocated at the longitudinal centerline of said housing member and theshort axis of said ellipse is located at a point immediately adjacentsaid cup member, whereby said center shroud terminates in a base whichis located at a point proximate the short axis of said ellipse.
 16. Thespray apparatus of claim 15 wherein the longitudinal cross section ofsaid housing member varies along said longitudinal axis of said housingmember from said circular first opening to said oval opposed opening,such variation in cross section being substantially equivalent to thecorresponding interior cross section of said boom shroud and said centershroud at such points along said longitudinal axis of said housingmember, whereby such correlative variations in such cross section ofsaid housing member produces a substantially constant pressure to suchair column through said housing member and around said center shroud andsaid boom shroud.
 17. An improved spray apparatus comprising, incombination: at least one spraying member, blower means for supplying acolumn of fluidized air, said blower means including a fan member spacedfrom and opposed to said spraying member, said blower means furtherincluding a housing member positioned adjacent said spraying member,said housing member being of hollow cross section and having open ends,said first open end of said housing member being substantially circularin cross section and said opposed open end of said housing member beinggenerally oval in cross section, said blower means further including acenter shroud member located within said housing member between said fanmember and said spraying member, whereby during operation of said sprayapparatus said column of fluidized air is propelled by said fan memberthrough said housing member and around said center shroud to envelopesaid spraying member and assist is dispersing such material exiting saidspraying member.
 18. An improved spray apparatus comprising, incombination: at least one spraying member, blower means for supplying acolumn of fluidized air, said blower means including a fan member spacedfrom and opposed to said spraying member, said blower means furtherincluding a housing member positioned adjacent said spraying member,said fan member being located within said housing member, said housingmember being of hollow cross section and having open ends, said firstopen end of said housing member being substantially circular in crosssection and said opposed open end of said housing member being generallyoval in cross section, said blower means further including a centershroud member located within said housing member between said fan memberand said rotary atomizing member, wherein the longitudinal cross sectionof said housing member varies along said longitudinal axis of saidhousing member from said circular first opening to said oval opposedopening, such variation in cross section being substantially equivalentto the corresponding interior cross section of said center shroud atsuch points along said longitudinal axis of said housing member, whereinsaid correlative variations in such cross section of said housing memberproduces a substantially constant pressure to such air column throughsaid housing member and around said center shroud, whereby duringoperation of said spray apparatus said column of fluidized air ispropelled by said fan member through said housing member and around saidcenter shroud to envelope said spraying member and assist in dispersingsuch material exiting said spraying member.